(a) Technical Field
The present invention relates to a housing for covering electronic/electrical components. More particularly, the present invention relates to a housing using a shape memory material which can actively control thermal conductivity in response to ambient temperature environments.
(b) Background Art
Generally, examples of electronic/electrical components generating a large amount of heat include Central Processing Units (CPUs), thermoelectric elements, power transistors, and batteries. These electronic/electrical components are accompanied by heat generation due to the intrinsic characteristics of materials and the electrical resistances occurring within connection portions between components.
With the development of electronic technology, electronic/electrical components are being further enhanced in their performance, are becoming faster in the processing speed, and are decreasing in their size. However, as the processing speed of components each having an equal area increases in proportion to the development of technology, thus more thermal energy is generated from the inside of components as a result.
Heat generated in these components shorten the lifespan of components, and/or deteriorates their functions, and often affects adjacent components as a result. In severe cases, heat may cause malfunction or data processing failures. Accordingly, various methods for effectively controlling heat generated in electronic/electrical components are being proposed.
For example, a housing using a composite containing filler with high thermal conductivity has been used to overcome heat generation limitations in electronic/electrical components for vehicles, particularly, battery systems. However, heat radiating composites have a limited thermal conductivity (e.g., about 10 W/mk to about 30 W/mk (injection direction) according to recent reports. Also, in components that are manufactured via an injection method, anisotropy of heat conduction occurs due to orientation of filler in the injection direction, and the thermal conductivity in the thickness direction is very low, one third to one fourth of that in the injection direction.
For effective heat radiation, the heat transfer path needs to be formed in accordance with the shape and characteristics of components. Thus, sufficient heat radiation effect can be achieved by convection, and most housing components can improve the heat radiation efficiency through the improvement of heat transfer characteristics in the thickness direction.
Also, a reduction in the performance of batteries may occur based on the actual use environments (temperature). Generally, the thermal runaway may occur in batteries that are operating in a high temperature environment, and the output reduction of batteries may frequently occur in a low temperature environment.
Some heat controlling materials have been developed from only one perspective, “heat radiation,” and are focused toward the improvement of thermal conductivity. When, however, heat insulation is needed, separate foaming or plastic materials with low thermal conductivity are used to manufacture a housing.
Thus, there are currently no materials on the market that can dynamically deal with different environmental fluctuations which may require heat insulation and/or heat radiation. That is, when heat insulation is excellent, heat radiation is deficient, and when heat radiation is excellent, heat insulation is deficient due to high thermal conductivity.
On solution is to provide a housing that is manufactured using a thermal insulator, and a blower is utilized or coolant is applied to the housing to enhance the heat radiation performance, causing the increase of the total weight. In order to overcome the above limitations, development of a housing material that can dynamically control heat conduction according to ambient environments and reduction in weight is needed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.